Ah, Polignac...good point about the duchess of Angouleme Marie Therese!
I suppose...but
I merely suppose, that Marie Therese had not a relationship with Marie Louise. When Marie Therese was released from the Temple prison and moved to Vienna´s court, she had seventeen years. She was a young girl who had passed through very hard times...her father had been guillotined, her mother had been guillotined, her beloved paternal aunt Elisabeth had been guillotined and her young brother the dauphin was "lost". I think that at the Vienna´s court she must have been suffered a good deal of emotional distress, in addition, due to the fact that she believed that her cousin emperor Francis II had done not enough to safe her parents from their ill-fate.
When Marie Therese was sent to the Vienna´s court, at the year 1795, Marie Louise, her second cousin, was a very little archduchess...remember that Marie Louise was born on December 1791! I believe that the poor traumatised girl of seventeen had not chances to enjoy herself with the archduchess aged four. And Marie Therese left Vienna on 1798, maybe on the beginnings of 1799...I don´t remember well. I know that on june 1799 she was marrying Louis-Antoine duke of Angouleme at Mitau, Lithuania, where she was established with her uncle, later Louis XVIII of France. So, when Marie Therese moved from Vienna to Mitau, Marie Louise was aged seven.
Marie Therese did not return to France after the defeat of Napoleon. She was really distrustful of the many french who had supported the Republic or, later, the Napoleon´s Empire. And Marie Louise, by this time, was playing her role as duchess of Parma.
A beautiful portrait of unfortunate cousin of Marie Louise:
